I read around here that the wrench with the 300 indicates when the next oil change is due. Not sure about the other one.
Have not seen the codes myslef - that function must either be disabled on my car, or the early New Jettas do not have it.
If you do a search on here you should be able to find more detail. If I remeber correctly there is also a way to reset that 'reminder' if it is to annoying.
Welcome to TDI Club btw.
Edit: This thread explains how to reset the code:
http://forums.tdiclub.com/showthread.php?t=146604&highlight=wrench
Otherwise - it seems that the 1st number indicates the miles till the next oilchange and the second number an estimate in hours or days till that oilchange.